Water in ponds, pits, lagoons and sumps from farm livestock buildings and operations, and in reservoirs, streams and the like, often contains solid materials and, when the water is pumped therefrom, the solid materials are sucked into the supply line. The solid materials, if not properly handled in the liquid, may either clog screens or pass into a pump or other equipment and interfere with the operation or cause serious damage to the equipment. The present invention is concerned with eliminating or minimizing the problem created by pumping liquids, primarily water, containing solid or semi-solid materials.
For the purpose of illustrating the present invention, reference will be made to the handling of liquid manure or the like, such as that usually encountered in raising livestock in confined areas. These liquid manure systems have become increasingly popular for handling animal wastes, particularly for large farming operations, in that greater mechanization and automation is possible with liquid manure systems than with other animal waste handling systems, thereby resulting in a savings in labor costs in handling the animal waste and creating greater productivity in the farming operation. Several types of liquid manure systems are commonly used. The animal waste may be stored in a pit beneath or near the building housing the animals, or the waste may be held in a lagoon for later disposal. Disposal of the liquid manure is generally accomplished by spraying the liquid onto a field and working it into the soil. The methods for transporting the liquid to the field may be of several types. One commonly used method is to pump the liquid from a pit into a vacuum tank, and then tow the tank through the field while spraying the liquid onto the field. Another method commonly used is to pipe the liquid manure from the lagoon or pit to the field, and to spray the liquid onto the field with spray guns similar to those used for water irrigation.
Problems are encountered frequently in liquid manure systems as a result of the presence of solid and semi-solid materials in the liquid manure. The liquid manure is more accurately called a slurry or sludge and often has solids from the animal waste as well as other foreign solid materials. For example, leaves, sticks and stones are often found in the liquid manure, especially when a lagoon is used to hold the liquid. Straw, wood chips or other bedding material, as well as hay and other animal food products are often found in the sludge or slurry making up the liquid manure. In liquid manure systems for fowl housing buildings, feathers from the birds and the carcasses of dead birds are often found in the manure slurry. Although much of a carcass will deteriorate rather quickly, the feathers and bones may remain.
When solids of any type are present in the liquid various handling difficulties arise. The solids can accumulate and obstruct the free flow of the liquid, thereby clogging pipes, hoses or other conduits used to pump the liquid containing solids from a pit, lagoon, stream or other body of water. Further, the solids or semi-solids can obstruct the nozzles in the spray guns or the spreader mechanism on the vacuum tank, thereby preventing the free flow of fluid therethrough. Still another problem encountered is that particularly large solids such as stones or sticks may damage the pumps used in transferring or transporting the liquid.
To prevent damage to the pumps of a liquid system, and to prevent clogging of spreader guns and nozzles, screens are used in the lines upstream from the vacuum pump. The screens prevent large debris, either solids or semi-solids, from entering and damaging the pump, and provide a more homogeneous liquid mixture or slurry flowing through the conduits. In a manure pit, for example, the screen will normally be disposed at or near the outlet from the pit. A problem which arises from the use of screens is that large solids such as sticks and stones or clumps of semi-solids may lodge in front of the screen and collect smaller material which otherwise would cause no problem in the manure handling system. The accumulation of large and small obstructions can block the flow of fluid through the screen, and the only suitable method for removing the blockage generally includes scraping the material from the front of the screen. Often, to do this, the worker may have to enter the pit to scrape the solids away. In piping systems which connect the lagoon or pit to a sprayer, a screen must be disposed at some location in the line upstream from the pump. Again, the solids can collect in front of the screen, and semi-solids which would otherwise not cause difficulty will fill the small areas between the larger solids and prevent the flow of liquid through the piping system. To clear the obstruction a portion of the piping system must be disassembled and the debris removed therefrom.
The cleaning methods for either of the above described systems require a substantial amount of time to perform and thereby decrease the efficiency of a liquid handling system. Further, once the obstruction has been cleared, the solids or semi-solids must be disposed of, this generally requiring some type of hand transporting and disposal. Many of the materials which cause blockage of liquid manure systems are found in a semi-solid state, and could be pulverized or chopped to pass through the liquid manure system. However, prior to this time no suitable device for pulverizing semi-solids in liquid handling systems has been available for general and convenient use.